Goodwill and Other Intangibles - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in the goodwill balance during the period			$ 0
Goodwill	$ 176,000,000		176,000,000		$ 176,000,000
Amortizable intangible assets related to property and casualty insurance acquisitions	30,000,000		30,000,000		34,000,000
Accumulated amortization	65,000,000		65,000,000		$ 62,000,000
Amortization of intangible assets	$ 1,000,000	$ 3,000,000	$ 4,000,000	$ 6,000,000